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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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621934ee7e
Updated patch adding a variant of RCU that permits sleeping in read-side critical sections. SRCU is as follows: o Each use of SRCU creates its own srcu_struct, and each srcu_struct has its own set of grace periods. This is critical, as it prevents one subsystem with a blocking reader from holding up SRCU grace periods for other subsystems. o The SRCU primitives (srcu_read_lock(), srcu_read_unlock(), and synchronize_srcu()) all take a pointer to a srcu_struct. o The SRCU primitives must be called from process context. o srcu_read_lock() returns an int that must be passed to the matching srcu_read_unlock(). Realtime RCU avoids the need for this by storing the state in the task struct, but SRCU needs to allow a given code path to pass through multiple SRCU domains -- storing state in the task struct would therefore require either arbitrary space in the task struct or arbitrary limits on SRCU nesting. So I kicked the state-storage problem up to the caller. Of course, it is not permitted to call synchronize_srcu() while in an SRCU read-side critical section. o There is no call_srcu(). It would not be hard to implement one, but it seems like too easy a way to OOM the system. (Hey, we have enough trouble with call_rcu(), which does -not- permit readers to sleep!!!) So, if you want it, please tell me why... [josht@us.ibm.com: sparse notation] Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
76 lines
2.9 KiB
Makefile
76 lines
2.9 KiB
Makefile
#
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# Makefile for the linux kernel.
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#
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obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
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exit.o itimer.o time.o softirq.o resource.o \
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sysctl.o capability.o ptrace.o timer.o user.o \
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signal.o sys.o kmod.o workqueue.o pid.o \
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rcupdate.o extable.o params.o posix-timers.o \
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kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
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hrtimer.o rwsem.o latency.o nsproxy.o srcu.o
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obj-$(CONFIG_STACKTRACE) += stacktrace.o
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obj-y += time/
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obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
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obj-$(CONFIG_LOCKDEP) += lockdep.o
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ifeq ($(CONFIG_PROC_FS),y)
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obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
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endif
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obj-$(CONFIG_FUTEX) += futex.o
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ifeq ($(CONFIG_COMPAT),y)
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obj-$(CONFIG_FUTEX) += futex_compat.o
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endif
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obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
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obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
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obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
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obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
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obj-$(CONFIG_SMP) += cpu.o spinlock.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
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obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
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obj-$(CONFIG_UID16) += uid16.o
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obj-$(CONFIG_MODULES) += module.o
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obj-$(CONFIG_KALLSYMS) += kallsyms.o
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obj-$(CONFIG_STACK_UNWIND) += unwind.o
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obj-$(CONFIG_PM) += power/
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obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
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obj-$(CONFIG_KEXEC) += kexec.o
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obj-$(CONFIG_COMPAT) += compat.o
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obj-$(CONFIG_CPUSETS) += cpuset.o
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obj-$(CONFIG_IKCONFIG) += configs.o
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obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
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obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
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obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
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obj-$(CONFIG_KPROBES) += kprobes.o
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obj-$(CONFIG_SYSFS) += ksysfs.o
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obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
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obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
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obj-$(CONFIG_SECCOMP) += seccomp.o
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obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
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obj-$(CONFIG_RELAY) += relay.o
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obj-$(CONFIG_UTS_NS) += utsname.o
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obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
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obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
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ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
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# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
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# needed for x86 only. Why this used to be enabled for all architectures is beyond
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# me. I suspect most platforms don't need this, but until we know that for sure
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# I turn this off for IA-64 only. Andreas Schwab says it's also needed on m68k
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# to get a correct value for the wait-channel (WCHAN in ps). --davidm
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CFLAGS_sched.o := $(PROFILING) -fno-omit-frame-pointer
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endif
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$(obj)/configs.o: $(obj)/config_data.h
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# config_data.h contains the same information as ikconfig.h but gzipped.
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# Info from config_data can be extracted from /proc/config*
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targets += config_data.gz
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$(obj)/config_data.gz: .config FORCE
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$(call if_changed,gzip)
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quiet_cmd_ikconfiggz = IKCFG $@
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cmd_ikconfiggz = (echo "static const char kernel_config_data[] = MAGIC_START"; cat $< | scripts/bin2c; echo "MAGIC_END;") > $@
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targets += config_data.h
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$(obj)/config_data.h: $(obj)/config_data.gz FORCE
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$(call if_changed,ikconfiggz)
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